Neo Geo Repair Tips

GadgetUK

Ace Ghost Pilot
Joined
Sep 27, 2013
Posts
1,323
Hi,

I've done a number of MVS 1 slot repairs recently and wanted to share it with people.

Backup RAM & Palette RAM Error
https://www.youtube.com/watch?v=YYWc4_uM0oA

Backup RAM & VRAM
https://www.youtube.com/watch?v=xKzP9NdAY8s

Z80 Error (MV1A / MV1AX)
https://www.youtube.com/watch?v=3FAHJmtqIKM

BIOS Removal Fix (MV1AX)
https://www.youtube.com/watch?v=ME21vLMQV80

Z80 Error - Neo-Buf Fix (MV1A)
https://www.youtube.com/watch?v=CGvGhdeA5ek

Z80 Error - SM1 Bypass (for when you cannot find a replacement SMD SM1) & Neo-Buf Bypass (relevant when you get stuck at cross hatch on a 1A or 1AX)
The Neo-Buf bypass could be relevant to people that find the 161 in 1 menu doesn't work properly on their board as in my case. I also found that when GA11 has a fault in one direction, the Neo SD menu doesn't work either.
https://www.youtube.com/watch?v=17IyUwCxKdQ
 
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ack

Ninja Combat Warrior
15 Year Member
Joined
Apr 9, 2009
Posts
538
Been watching these, great set of videos!
 

GadgetUK

Ace Ghost Pilot
Joined
Sep 27, 2013
Posts
1,323
Thanks! Another tip here - helping a friend working on his 1FZ, he worked out that the 245 had failed related to the LO ROM, after we worked through trying to work out why no sprites. He had the S1 layer, previously swapped out the 2K VRAMs (as they had failed with error), and after he swapped the 245 he saw coloured lines down the screen instead of sprites. Suspected LO ROM. Just removed mine to see how it behaves without a LO ROM:-

IMG_4711.JPG

Also, here's the link to that backup RAM diagram I did which may help with BRAM errors:-
http://www.neo-geo.com/forums/showthread.php?275473-MV-1FZ-Backup-RAM-Help
 
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superfry63

Kuroko's Training Dummy
Joined
May 13, 2018
Posts
76
Huge fan of your videos, both Neo Geo and everything else you post.

Thanks for this!
 

neoslacker

n00b
Joined
Sep 6, 2018
Posts
26
Good vids mate. The one you did where you checked the logic was particularly interesting.

I have an stock AES 3-6 which yellow screens (I haven't got the diag bios yet but its on the way).

As far as I can tell, One of the Video SRAM chips (CXK5814P-35L) is responsible (no broken traces anywhere).

Is there a way for me to check that RAM onboard before I pull it? I have a logic probe.

Board is here

- NM

Hi,

I've done a number of MVS 1 slot repairs recently and wanted to share it with people.

Backup RAM & Palette RAM Error
https://www.youtube.com/watch?v=YYWc4_uM0oA

Backup RAM & VRAM
https://www.youtube.com/watch?v=xKzP9NdAY8s

Z80 Error (MV1A / MV1AX)
https://www.youtube.com/watch?v=3FAHJmtqIKM

BIOS Removal Fix (MV1AX)
https://www.youtube.com/watch?v=ME21vLMQV80

Z80 Error - Neo-Buf Fix (MV1A)
https://www.youtube.com/watch?v=CGvGhdeA5ek

Z80 Error - SM1 Bypass (for when you cannot find a replacement SMD SM1) & Neo-Buf Bypass (relevant when you get stuck at cross hatch on a 1A or 1AX)
The Neo-Buf bypass could be relevant to people that find the 161 in 1 menu doesn't work properly on their board as in my case. I also found that when GA11 has a fault in one direction, the Neo SD menu doesn't work either.
https://www.youtube.com/watch?v=17IyUwCxKdQ
 

GadgetUK

Ace Ghost Pilot
Joined
Sep 27, 2013
Posts
1,323
Not really! You can check if the OE and WE are changing state, BUT... At any given point in time they might be stalled depending on what the system is actually doing. 99 times out of 100 those chips just fail. I would buy two, since they do both fail sometimes at the same time. Probing the data and address lines with a logic probe probably wont reveal much, unless you see one that's open circuit and floating.
 

GadgetUK

Ace Ghost Pilot
Joined
Sep 27, 2013
Posts
1,323
Some more recent ones:-

6 Slot Part 1
https://www.youtube.com/watch?v=0gZh8FQo19w

6 Slot Part 2
https://www.youtube.com/watch?v=Q7QFkJxcFdI

MV1A/X (7 Boards - Various Faults) Part 1
https://www.youtube.com/watch?v=5Xs8bgKPRaw

MV1A/X (7 Boards - Various Faults) Part 2
https://www.youtube.com/watch?v=UnSGLKsPmTg

MV1A/X (7 Boards - Various Faults) Part 3
https://www.youtube.com/watch?v=yl75umrfgi0

Neo Geo CD PSU Repair
https://www.youtube.com/watch?v=Pr21GlJdNAo

I also have coming up a Neo CD, MV1B, 2 x MV1F and another 1FZ.
 

GadgetUK

Ace Ghost Pilot
Joined
Sep 27, 2013
Posts
1,323
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